The success achieved by the SS methods must be measured by the achievements of the final applications.
They are generally too difficult to evaluate because graphical applications often require an expert user.
For this reason, it is necessary to use application-independent measures of accuracy.
Thus, to evaluate our results on segmentation, we chose accuracy, intersection-over-union, precision, and recall metrics as
validation measures (from Csurka et al.  [1]}).
The intersection-over-union (IoU) is defined by
\(\text{IoU} = \sum _{i}^N \frac{P_i \cap Y_i}{P_i \cup Y_i} = \sum _{i}^N \frac{\mathit {TP}_i}{\mathit {TP}_i + \mathit {FP}_i + \mathit {FN}_i},\) 
